The overall objective of this proposal is to evaluate the role of Vitamin A (Retinol) in the prevention of cancer. Our approach involves a multidisciplinary cancer research effort and the following three investigations are planned: 1) the value of Vitamin A (Retinol) on the reduction of risk for skin cancer; 2) the safety and adverse health effects of chronic pharmacologic doses of Vitamin A (Retinol); 3) the plasma concentration levels as well as the concordance between prescribed and actual intake of Vitamin A (Retinol) in persons participating in the chemoprevention study.